Elastomeric compounds incorporating metal-treated carbon blacks

ABSTRACT

Disclosed are elastomeric compounds including an elastomer and an aggregate comprising a carbon phase and a metal-containing species phase, optionally including a coupling agent. Also disclosed is an aggregate comprising a carbon phase and a metal-containing species phase. A variety of elastomers and formulations employing such elastomers are contemplated and disclosed. Elastomeric compounds incorporating an elastomer and the aggregate are also disclosed. Also disclosed are methods for preparing elastomers compounded with the aggregate.

FIELD OF THE INVENTION

The present invention relates to novel aggregates and elastomericcompounds. More particularly, the present invention relates tometal-containing carbon blacks and elastomeric compounds incorporatingmetal-containing carbon blacks, such as aluminum-treated or zinc-treatedcarbon blacks, and products manufactured from such compounds.

BACKGROUND OF THE INVENTION

Carbon blacks are widely used as pigments, fillers and reinforcingagents in the compounding and preparation of rubber and otherelastomeric compounds. Carbon blacks are particularly useful asreinforcing agents in the preparation of elastomeric compounds used inthe manufacture of tires.

Carbon blacks are generally produced in a furnace-type reactor bypyrolyzing a hydrocarbon feedstock with hot combustion gases to producecombustion products containing particulate carbon black. Carbon blackexists in the form of aggregates. The aggregates, in turn are formed ofcarbon black particles. However, carbon black particles do not generallyexist independently of the carbon black aggregate. Carbon blacks aregenerally characterized on the basis of analytical properties,including, but not limited to particle size and specific surface area;aggregate size, shape, and distribution; and chemical and physicalproperties of the surface. The properties of carbon blacks areanalytically determined by tests known to the art. For example, nitrogenadsorption surface area (measured by ASTM test procedure D3037-Method A)and cetyl-trimethyl ammonium bromide adsorption value (CTAB) (measuredby ASTM test procedure D3765 [09.01]), are measures of specific surfacearea. Dibutylphthalate absorption of the crushed (CDBP) (measured byASTM test procedure D3493-86) and uncrushed (DBP) carbon black (measuredby ASTM test procedure D2414-93), relates to the aggregate structure.The bound rubber value relates to the surface activity of the carbonblack. The properties of a given carbon black depend upon the conditionsof manufacture and may be modified, e.g., by altering temperature,pressure, feedstock, residence time, quench temperature, throughput, andother parameters.

It is generally desirable in the production of tires to employ carbonblack-containing compounds when constructing the tread and otherportions of the tire. For example, a suitable tread compound will employan elastomer compounded to provide high abrasion resistance and goodhysteresis balance at different temperatures. A tire having highabrasion resistance is desirable because abrasion resistance isproportional to tire life. The physical properties of the carbon blackdirectly influence the abrasion resistance and hysteresis of the treadcompound. Generally, a carbon black with a high surface area and smallparticle size will impart a high abrasion resistance and high hysteresisto the tread compound. Carbon black loading also affects the abrasionresistance of the elastomeric compounds. Abrasion resistance increaseswith increased loading, at least to an optimum point, beyond whichabrasion resistance actually decreases.

The hysteresis of an elastomeric compound relates to the energydissipated under cyclic deformation. In other words, the hysteresis ofan elastomeric composition relates to the difference between the energyapplied to deform the elastomeric composition and the energy released asthe elastomeric composition recovers to its initial undeformed state.Hysteresis is characterized by a loss tangent, tan δ, which is a ratioof the loss modulus to the storage modulus (that is, viscous modulus toelastic modulus). Tires made with a tire tread compound having a lowerhysteresis measured at higher temperatures, such as 40° C. or higher,will have reduced rolling resistance, which in turn, results in reducedfuel consumption by the vehicle using the tire. At the same time, a tiretread with a higher hysteresis value measured at low temperature, suchas 0° C. or lower, will result in a tire with high wet traction and skidresistance which will increase driving safety. Thus, a tire treadcompound demonstrating low hysteresis at high temperatures and highhysteresis at low temperatures can be said to have a good hysteresisbalance.

There are many other applications where it is useful to provide anelastomer exhibiting a good hysteresis balance but where the abrasionresistance is not an important factor. Such applications include but arenot limited to tire components such as undertread, wedge compounds,sidewall, carcass, apex, bead filler and wire skim; engine mounts; andbase compounds used in industrial drive and automotive belts.

Silica is also used as a reinforcing agent (or filler) for elastomers.However, using silica alone as a reinforcing agent for elastomer leadsto poor performance compared to the results obtained with carbon blackalone as the reinforcing agent. It is theorized that strongfiller-filler interaction and poor filler-elastomer interaction accountsfor the poor performance of silica. The silica-elastomer interaction canbe improved by chemically bonding the two with a chemical couplingagent, such as bis(3-triethoxysilylpropyl)tetra-sulfane, commerciallyavailable as Si-69 from Degussa AG, Germany. Coupling agents such asSi-69 create a chemical linkage between the elastomer and the silica,thereby coupling the silica to the elastomer.

When the silica is chemically coupled to the elastomer, certainperformance characteristics of the resulting elastomeric composition areenhanced. When incorporated into vehicle tires, such elastomericcompounds provide improved hysteresis balance. However, elastomercompounds containing silica as the primary reinforcing agent exhibit lowthermal conductivity, high electrical resistivity, high density and poorprocessability.

When carbon black alone is used as a reinforcing agent in elastomericcompositions, it does not chemically couple to the elastomer but thecarbon black surface provides many sites for interacting with theelastomer. While the use of a coupling agent with carbon black mightprovide some improvement in performance to an elastomeric composition,the improvement is not comparable to that obtained when using a couplingagent with silica.

It has been established that the hysteresis of filled compounds ismainly related to the filler network formed in the polymer matrix whichcauses high hysteresis at high temperature and low hysteresis at lowtemperature. This is undesirable for tire applications. The main factorto control filler networking is the filler-filler interaction.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide filler compoundswhich can be incorporated into elastomeric compounds. Particularly, itis an object to provide an elastomeric compound incorporatingmetal-treated carbon blacks, such as aluminum-treated or zinc-treatedcarbon blacks. It is yet another object of the present invention toprovide an elastomeric compound incorporating metal-treated carbonblacks, wherein the carbon black may be efficiently coupled to theelastomer with a coupling agent. Such a carbon black may be employed forexample, in tire compounds, industrial rubber products and other rubbergoods. It is a further object of the present invention to providemetal-treated carbon black/elastomeric formulations using a variety ofelastomers useful in a variety of product applications.

Additional features and advantages of the present invention will be setforth in part in the description which follows, and in part will beapparent from the description, or may be learned by the practice of thepresent invention. The objectives and other advantages of the presentinvention may be realized and obtained by means of the elements andcombinations particularly pointed out in the written description and theclaims.

To achieve these and other advantages, and in accordance with thepurpose of the present invention, as embodied and broadly describedherein, the present invention relates to metal-treated carbon blackswhich are aggregates containing at least a carbon phase and ametal-containing species phase. The present invention is also directedto an elastomeric compound including an elastomer and a metal-treatedcarbon black, and optionally including a coupling agent. A variety ofelastomers and formulations employing such elastomers are contemplatedand disclosed. Elastomeric compounds incorporating an elastomer and ametal-treated carbon black are also disclosed. Also disclosed aremethods for preparing elastomeric compounds with the metal-treatedcarbon blacks and products manufactured from such compounds.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a portion of one type of carbon blackreactor which may be used to produce the treated carbon blacks of thepresent invention.

FIG. 2 is a graph demonstrating hysteresis values at different strainsat 70° C. on elastomeric compositions of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to metal-treated carbon blacks. Thesemetal-treated carbon blacks can be incorporated into elastomericcompounds for a variety of uses, such as tire applications. Themetal-treated carbon blacks are aggregates containing at least a carbonphase and a metal-containing species phase. The metal-containing speciesinclude compounds containing aluminum, zinc, magnesium, calcium,titanium, vanadium, cobalt, nickel, zirconium, tin, antimony, chromium,neodymium, lead, tellurium, barium, cesium, iron, and molybdenum.Preferably, the metal-containing species phase is an aluminum- orzinc-containing species phase. The metal-containing species include, butare not limited to, oxides of metals. The metal-containing species phasecan be distributed through at least a portion of the aggregate and is anintrinsic part of the aggregate. These metal-treated carbon blacks maybe incorporated into elastomeric compounds and can lead to desirableproperties by compounding an elastomer with a metal-treated carbonblack.

Metal-treated carbon black aggregates do not represent a mixture ofdiscrete carbon black aggregates and discrete metal-containingaggregates. Rather, the metal-treated carbon black aggregates of thepresent invention include at least one metal-containing regionconcentrated at or near the surface of the aggregate (but part of theaggregate) or within the aggregate. Thus, as stated earlier, themetal-treated carbon black aggregates can be described as aggregatescomprising a carbon phase and a metal-containing species phase. Theaggregates thus contain at least two phases, one of which is carbon andthe other of which is a metal-containing species. The metal-containingspecies phase that is part of the aggregate is not attached to a carbonblack aggregate like a silane coupling agent, but actually is part ofthe same aggregate as the carbon phase. Further, it is within the boundsof the present invention to have a metal-treated carbon black containingmore than one type of a metal-containing species phase or themetal-treated carbon black can also contain a silicon-containing speciesphase and/or a boron-containing species phase. For example, themetal-treated carbon black of the present invention can have anaggregate comprising a carbon phase, an aluminum-containing speciesphase, and a zinc-containing species phase. Accordingly, themetal-treated carbon black of the present invention can have two or moredifferent types of metal-containing species phases and/or additionalnon-metal species phases.

As indicated above, the aggregate of the present invention canadditionally contain a silicon-containing species phase as described inU.S. patent applications Ser. Nos. 08/446,141; 08/446,142; 08/528,895;and 08/750,017, and PCT Published Application No. WO 96/37547, allincorporated in their entireties by reference.

The metal-treated carbon blacks may be obtained by manufacturing thecarbon black in the presence of volatilazable or decomposiblemetal-containing compounds. Such carbon blacks are preferably producedin a modular or "staged," furnace carbon black reactor as depicted inFIG. 1. The furnace carbon black reactor has a combustion zone 1, with azone of converging diameter 2; a feedstock injection zone withrestricted diameter 3; and a reaction zone 4.

To produce carbon blacks with the reactor described above, hotcombustion gases are generated in combustion zone 1 by contacting aliquid or gaseous fuel with a suitable oxidant stream such as air,oxygen, or mixtures of air and oxygen. Among the fuels suitable for usein contacting the oxidant stream in combustion zone 1, to generate thehot combustion gases, are included any readily combustible gas, vapor orliquid streams such as natural gas, hydrogen, methane, acetylene,alcohols, or kerosene. It is generally preferred, however, to use fuelshaving a high content of carbon-containing components and in particular,hydrocarbons. The ratio of air to fuel varies with the type of fuelutilized. When natural gas is used to produce the carbon blacks of thepresent invention, the ratio of air to fuel may be from about 10:1 toabout 1000:1. To facilitate the generation of hot combustion gases, theoxidant stream may be pre-heated.

The hot combustion gas stream flows downstream from zones 1 and 2 intozones 3 and 4. The direction of the flow of hot combustion gases isshown in FIG. 1 by the arrow. Carbon black feedstock, 6, is introducedat point 7 into the feedstock injection zone 3. The feedstock isinjected into the gas stream through nozzles designed for optimaldistribution of the oil in the gas stream. Such nozzles may be eithersingle or bi-fluid. Bi-fluid nozzles may use steam or air to atomize thefuel. Single-fluid nozzles may be pressure atomized or the feedstock canbe directly injected into the gas-stream. In the latter instance,atomization occurs by the force of the gas-stream.

Carbon blacks can be produced by the pyrolysis or partial combustion ofany liquid or gaseous hydrocarbon. Preferred carbon black feedstocksinclude petroleum refinery sources such as decanted oils from catalyticcracking operations, as well as the by-products from coking operationsand olefin manufacturing operations.

The mixture of carbon black-yielding feedstock and hot combustion gasesflows downstream through zone 3 and 4. In the reaction zone portion ofthe reactor, the feedstock is pyrolyzed to carbon black. The reaction isarrested in the quench zone of the reactor. Quench 8 is locateddownstream of the reaction zone and sprays a quenching fluid, generallywater, into the stream of newly formed carbon black particles. Thequench serves to cool the carbon black particles and to reduce thetemperature of the gaseous stream and decrease the reaction rate. Q isthe distance from the beginning of reaction zone 4 to quench point 8,and will vary according to the position of the quench. Optionally,quenching may be staged, or take place at several points in the reactor.

After the carbon black is quenched, the cooled gases and carbon blackpass downstream into any conventional cooling and separating meanswhereby the carbon black is recovered. The separation of the carbonblack from the gas stream is readily accomplished by conventional meanssuch as a precipitator, cyclone separator, bag filter or other meansknown to those skilled in the art. After the carbon black has beenseparated from the gas stream, it is optionally subjected to apelletization step.

The metal-treated carbon blacks of the present invention may be made byintroducing a volatilizable metal-containing compound into the carbonblack reactor at a point upstream of the quench zone. Usefulvolatilizable compounds (i.e., the metal-containing compounds) includeany compound, which is volatilizable at carbon black reactortemperatures. Examples include volatilizable or decomposible compoundscontaining aluminum, zinc, magnesium, calcium, titanium, vanadium,cobalt, nickel, zirconium, tin, antimony, chromium, neodymium, lead,tellurium, barium, cesium, iron, and molybdenum. Specific examplesinclude, but are not limited to, butoxides such as Aluminum IIIn-Butoxide and Aluminum III s-Butoxide, and propoxides, such as Al IIIiso-propoxide. Examples of suitable zinc-containing compounds include,but are not limited to, zinc napthenate and zinc octoate. Other examplesinclude, but are not limited to, magnesium ethoxide, magnesiumisopropoxide, calcium propoxide, titanium isopropoxide, cobaltousnapthenate, tin diethyl oxide, neodymium oxalate, and the like. The flowrate of the volatilizable compound will determine the weight percent ofmetal in the treated carbon black. The weight percent of the elementalmetal (e.g., elemental aluminum or zinc) in the treated carbon blackgenerally ranges from about 0.1% to 25%, by weight of the aggregate, butmay be adjusted to any desired level, such as up to 50% by weight,greater than 50% by weight, or up to 99% by weight of the aggregate.

The volatilizable compound may be premixed with the carbon black-formingfeedstock and introduced with the feedstock into the reaction zone.Alternatively, the volatilizable compound may be introduced to thereaction zone separately from the feedstock injection point. Suchintroduction may be upstream or downstream from the feedstock injectionpoint, provided the volatilizable compound is introduced upstream fromthe quench zone. For example, referring to FIG. 1, the volatilizablecompound may be introduced to zone Q at point 12 or any other point inthe zone. Upon volatilization and exposure to high temperatures in thereactor, the compound decomposes, and reacts with other species in thereaction zone, yielding metal-treated carbon black, such that the metal,or metal-containing species, becomes an intrinsic part of the carbonblack.

Besides volatalizable compounds, decomposible metal-containing compoundswhich are not necessarily volatilizable can also be used to yield themetal-treated carbon black.

As discussed in further detail below, if the volatilizable compound isintroduced substantially simultaneously with the feedstock, themetal-treated regions are distributed throughout at least a portion ofthe carbon black aggregate.

In a second embodiment of the present invention, the volatilizablecompound is introduced to the reaction zone at a point after carbonblack formation has commenced but before the reaction stream has beensubjected to the quench. In this embodiment, metal-treated carbon blackaggregates are obtained in which the metal-containing species phase isconcentrated primarily at or near the surface of the aggregate.

It has been found by the present inventors that the elastomericcompounds incorporating a metal-treated carbon black may be additionallycompounded with one or more coupling agents to further enhance theproperties of the elastomeric compound. Coupling agents, as used herein,include, but are not limited to, compounds that are capable of couplingfillers such as carbon black or silica to an elastomer. Coupling agentsuseful for coupling silica or carbon black to an elastomer, are expectedto be useful with the metal-treated carbon blacks. Useful couplingagents include, but are not limited to, silane coupling agents such asbis(3-triethoxysilylpropyl)tetrasulfane (Si-69),3-thiocyanatopropyl-triethoxy silane (Si-264, from Degussa AG, Germany),γ-mercaptopropyl-trimethoxy silane (A189, from Union Carbide Corp.,Danbury, Conn.); zirconate coupling agents, such as zirconiumdineoalkanolatodi(3-mercapto)propionato-O (NZ 66A, from KenrichPetrochemicals, Inc., of Bayonne, N.J.); titanate coupling agents; nitrocoupling agents such asN,N'-bis(2-methyl-2-nitropropyl)-1,6-diaminohexane (Sumifine 1162, fromSumitomo Chemical Co., Japan); and mixtures of any of the foregoing. Thecoupling agents may be provided as a mixture with a suitable carrier,for example X50-S which is a mixture of Si-69 and N330 carbon black,available from Degussa AG.

The metal-treated carbon black may also be modified to have at least oneorganic group attached to the metal-treated carbon black. Alternatively,or in addition, a mixture of metal-treated carbon black and a modifiedcarbon black having at least one attached organic group may be used. Inaddition, it is within the bounds of the present invention to use amixture of two or more types of metal-treated carbon black in theelastomeric compositions of the present invention.

Methods for attaching organic groups to carbon black and a furtherdiscussion of the types of organic groups that can be attached can befound in U.S. patent application Ser. Nos. 08/356,660; 08/572,525; and08/356,459, now U.S. Pat. No. 5,559,169; and PCT Published ApplicationsNos. WO 96/18688 and WO 96/18696, the disclosures of which are fullyincorporated by reference herein.

One process for attaching an organic group to the carbon black involvesthe reaction of at least one diazonium salt with a carbon black in theabsence of an externally applied current sufficient to reduce thediazonium salt. That is, the reaction between the diazonium salt and thecarbon black proceeds without an external source of electrons sufficientto reduce the diazonium salt. Mixtures of different diazonium salts maybe used in the process of the invention. This process can be carried outunder a variety of reaction conditions and in any type of reactionmedium, including both protic and aprotic solvent systems or slurries.

In another process, at least one diazonium salt reacts with a carbonblack in a protic reaction medium. Mixtures of different diazonium saltsmay be used in this process of the invention. This process can also becarried out under a variety of reaction conditions.

Preferably, in both processes, the diazonium salt is formed in situ. Ifdesired, in either process, the carbon black product can be isolated anddried by means known in the art. Furthermore, the resultant carbon blackproduct can be treated to remove impurities by known techniques. Thevarious preferred embodiments of these processes are discussed below.

These processes can be carried out under a wide variety of conditionsand in general are not limited by any particular condition. The reactionconditions must be such that the particular diazonium salt issufficiently stable to allow it to react with the carbon black. Thus,the processes can be carried out under reaction conditions where thediazonium salt is short lived. The reaction between the diazonium saltand the carbon black occurs, for example, over a wide range of pH andtemperature. The processes can be carried out at acidic, neutral, andbasic pH. Preferably, the pH ranges from about 1 to 9. The reactiontemperature may preferably range from 0° C. to 100° C.

Diazonium salts, as known in the art, may be formed for example by thereaction of primary amines with aqueous solutions of nitrous acid. Ageneral discussion of diazonium salts and methods for their preparationis found in Morrison and Boyd, Organic Chemistry, 5th Ed., pp. 973-983,(Allyn and Bacon, Inc. 1987) and March, Advanced Organic Chemistry:Reactions, Mechanisms, and Structures, 4th Ed., (Wiley, 1992). Accordingto this invention, a diazonium salt is an organic compound having one ormore diazonium groups.

The diazonium salt may be prepared prior to reaction with the carbonblack or, more preferably, generated in situ using techniques known inthe art. In situ generation also allows the use of unstable diazoniumsalts such as alkyl diazonium salts and avoids unnecessary handling ormanipulation of the diazonium salt. In particularly preferred processes,both the nitrous acid and the diazonium salt are generated in situ.

A diazonium salt, as is known in the art, may be generated by reacting aprimary amine, a nitrite and an acid. The nitrite may be any metalnitrite, preferably lithium nitrite, sodium nitrite, potassium nitrite,or zinc nitrite, or any organic nitrite such as for exampleisoamylnitrite or ethylnitrite. The acid may be any acid, inorganic ororganic, which is effective in the generation of the diazonium salt.Preferred acids include nitric acid, HNO₃, hydrochloric acid, HCl, andsulfuric acid, H₂ SO₄.

The diazonium salt may also be generated by reacting the primary aminewith an aqueous solution of nitrogen dioxide. The aqueous solution ofnitrogen dioxide, NO₂ /H₂ O, provides the nitrous acid needed togenerate the diazonium salt.

Generating the diazonium salt in the presence of excess HCl may be lesspreferred than other alternatives because HCl is corrosive to stainlesssteel. Generation of the diazonium salt with NO₂ /H₂ O has theadditional advantage of being less corrosive to stainless steel or othermetals commonly used for reaction vessels. Generation using H₂ SO₄/NaNO₂ or HNO₃ /NaNO₂ are also relatively non-corrosive.

In general, generating a diazonium salt from a primary amine, a nitrite,and an acid requires two equivalents of acid based on the amount ofamine used. In an in situ process, the diazonium salt can be generatedusing one equivalent of the acid. When the primary amine contains astrong acid group, adding a separate acid may not be necessary. The acidgroup or groups of the primary amine can supply one or both of theneeded equivalents of acid. When the primary amine contains a strongacid group, preferably either no additional acid or up to one equivalentof additional acid is added to a process of the invention to generatethe diazonium salt in situ. A slight excess of additional acid may beused. One example of such a primary amine is para-aminobenzenesulfonicacid (sulfanilic acid).

In general, diazonium salts are thermally unstable. They are typicallyprepared in solution at low temperatures, such as 0-5° C., and usedwithout isolation of the salt. Heating solutions of some diazonium saltsmay liberate nitrogen and form either the corresponding alcohols inacidic media or the organic free radicals in basic media.

However, the diazonium salt need only be sufficiently stable to allowreaction with the carbon black. Thus, the processes can be carried outwith some diazonium salts otherwise considered to be unstable andsubject to decomposition. Some decomposition processes may compete withthe reaction between the carbon black and the diazonium salt and mayreduce the total number of organic groups attached to the carbon black.Further, the reaction may be carried out at elevated temperatures wheremany diazonium salts may be susceptible to decomposition. Elevatedtemperatures may also advantageously increase the solubility of thediazonium salt in the reaction medium and improve its handling duringthe process. However, elevated temperatures may result in some loss ofthe diazonium salt due to other decomposition processes.

Reagents can be added to form the diazonium salt in situ, to asuspension of carbon black in the reaction medium, for example, water.Thus, a carbon black suspension to be used may already contain one ormore reagents to generate the diazonium salt and the processaccomplished by adding the remaining reagents.

Reactions to form a diazonium salt are compatible with a large varietyof functional groups commonly found on organic compounds. Thus, only theavailability of a diazonium salt for reaction with a carbon black limitsthe processes of the invention.

The processes can be carried out in any reaction medium which allows thereaction between the diazonium salt and the carbon black to proceed.Preferably, the reaction medium is a solvent-based system. The solventmay be a protic solvent, an aprotic solvent, or a mixture of solvents.Protic solvents are solvents, like water or methanol, containing ahydrogen attached to an oxygen or nitrogen and thus are sufficientlyacidic to form hydrogen bonds. Aprotic solvents are solvents which donot contain an acidic hydrogen as defined above. Aprotic solventsinclude, for example, solvents such as hexanes, tetrahydrofuran (THF),acetonitrile, and benzonitrile. For a discussion of protic and aproticsolvents see Morrison and Boyd, Organic Chemistry, 5th Ed., pp. 228-231,(Allyn and Bacon, Inc. 1987).

The processes are preferably carried out in a protic reaction medium,that is, in a protic solvent alone or a mixture of solvents whichcontains at least one protic solvent. Preferred protic media include,but are not limited to water, aqueous media containing water and othersolvents, alcohols, and any media containing an alcohol, or mixtures ofsuch media.

The reaction between a diazonium salt and a carbon black can take placewith any type of carbon black, for example, in fluffy or pelleted form.In one embodiment designed to reduce production costs, the reactionoccurs during a process for forming carbon black pellets. For example, acarbon black product of the invention can be prepared in a dry drum byspraying a solution or slurry of a diazonium salt onto a carbon black.Alternatively, the carbon black product can be prepared by pelletizing acarbon black in the presence of a solvent system, such as water,containing the diazonium salt or the reagents to generate the diazoniumsalt in situ. Aqueous solvent systems are preferred. Accordingly,another embodiment provides a process for forming a pelletized carbonblack comprising the steps of: introducing a carbon black and an aqueousslurry or solution of a diazonium salt into a pelletizer, reacting thediazonium salt with the carbon black to attach an organic group to thecarbon black, and pelletizing the resulting carbon black having anattached organic group. The pelletized carbon black product may then bedried using conventional techniques.

In general, the processes produce inorganic by-products, such as salts.In some end uses, such as those discussed below, these by-products maybe undesirable. Several possible ways to produce a carbon black productwithout unwanted inorganic by-products or salts are as follows:

First, the diazonium salt can be purified before use by removing theunwanted inorganic by-product using means known in the art. Second, thediazonium salt can be generated with the use of an organic nitrite asthe diazotization agent yielding the corresponding alcohol rather thanan inorganic salt. Third, when the diazonium salt is generated from anamine having an acid group and aqueous NO₂, no inorganic salts areformed. Other ways may be known to those of skill in the art.

In addition to the inorganic by-products, a process may also produceorganic by-products. They can be removed, for example, by extractionwith organic solvents. Other ways of obtaining products without unwantedorganic by-products may be known to those of skill in the art andinclude washing or removal of ions by reverse osmosis.

The reaction between a diazonium salt and a carbon black forms a carbonblack product having an organic group attached to the carbon black. Thediazonium salt may contain the organic group to be attached to thecarbon black. It may be possible to produce the carbon black products ofthis invention by other means known to those skilled in the art.

The organic group may be an aliphatic group, a cyclic organic group, oran organic compound having an aliphatic portion and a cyclic portion. Asdiscussed above, the diazonium salt employed in the processes can bederived from a primary amine having one of these groups and beingcapable of forming, even transiently, a diazonium salt. The organicgroup may be substituted or unsubstituted, branched or unbranched.Aliphatic groups include, for example, groups derived from alkanes,alkenes, alcohols, ethers, aldehydes, ketones, carboxylic acids, andcarbohydrates. Cyclic organic groups include, but are not limited to,alicyclic hydrocarbon groups (for example, cycloalkyls, cycloalkenyls),heterocyclic hydrocarbon groups (for example, pyrrolidinyl, pyrrolinyl,piperidinyl, morpholinyl, and the like), aryl groups (for example,phenyl, naphthyl, anthracenyl, and the like), and heteroaryl groups(imidazolyl, pyrazolyl, pyridinyl, thienyl, thiazolyl, furyl, indolyl,and the like). As the stearic hindrance of a substituted organic groupincreases, the number of organic groups attached to the carbon blackfrom the reaction between the diazonium salt and the carbon black may bediminished.

When the organic group is substituted, it may contain any functionalgroup compatible with the formation of a diazonium salt. Preferredfunctional groups include, but are not limited to, R, OR, COR, COOR,OCOR, carboxylate salts such as COOLi, COONa, COOK, COO⁻ NR₄ ⁺, halogen,CN, NR₂, SO₃ H, sulfonate salts such as SO₃ Li, SO₃ Na, SO₃ K, SO₃ ⁻ NR₄⁺, OSO₃ H, OSO₃ ⁻ salts, NR(COR), CONR₂, NO₂, PO₃ H₂, phosphonate saltssuch as PO₃ HNa and PO₃ Na₂, phosphate salts such as OPO₃ HNa and OPO₃Na₂, N═NR, NR₃ ⁺ X⁻, PR₃ ⁺ X⁻, S_(k) R, SSO₃ H, SSO₃ ⁻ salts, SO₂ NRR',SO₂ SR, SNRR', SNQ, SO₂ NQ, CO₂ NQ, S-(1,4-piperazinediyl)-SR,2-(1,3-dithianyl) 2-(1,3-dithiolanyl), SOR, and SO₂ R. R and R', whichcan be the same or different, are independently hydrogen, branched orunbranched C₁ -C₂₀ substituted or unsubstituted, saturated orunsaturated hydrocarbon, e.g., alkyl, alkenyl, alkynyl, substituted orunsubstituted aryl, substituted or unsubstituted heteroaryl, substitutedor unsubstituted alkylaryl, or substituted or unsubstituted arylalkyl.The integer k ranges from 1-8 and preferably from 2-4. The anion X⁻ is ahalide or an anion derived from a mineral or organic acid. Q is(CH₂)_(w), (CH₂)_(x) O(CH₂)_(z), (CH₂)_(x) NR(CH₂)_(z), or (CH₂)_(x)S(CH₂)_(z), where w is an integer from 2 to 6 and x and z are integersfrom 1 to 6.

A preferred organic group is an aromatic group of the formula A_(y)Ar--, which corresponds to a primary amine of the formula A_(y) ArNH₂.In this formula, the variables have the following meanings: Ar is anaromatic radical such as an aryl or heteroaryl group. Preferably, Ar isselected from the group consisting of phenyl, naphthyl, anthracenyl,phenanthrenyl, biphenyl, pyridinyl, benzothiadiazolyl, andbenzothiazolyl; A is a substituent on the aromatic radical independentlyselected from a preferred functional group described above or A is alinear, branched or cyclic hydrocarbon radical (preferably containing 1to 20 carbon atoms), unsubstituted or substituted with one or more ofthose functional groups; and y is an integer from 1 to the total numberof --CH radicals in the aromatic radical. For instance, y is an integerfrom 1 to 5 when Ar is phenyl, 1 to 7 when Ar is naphthyl, 1 to 9 whenAr is anthracenyl, phenanthrenyl, or biphenyl, or 1 to 4 when Ar ispyridinyl. In the above formula, specific examples of R and R' are NH₂--C₆ H₄ --, CH₂ CH₂ --C₆ H₄ --NH₂, CH₂ --C₆ H₄ --NH₂, and C₆ H₅.

Another preferred set of organic groups which may be attached to thecarbon black are organic groups substituted with an ionic or anionizable group as a functional group. An ionizable group is one whichis capable of forming an ionic group in the medium of use. The ionicgroup may be an anionic group or a cationic group and the ionizablegroup may form an anion or a cation.

Ionizable functional groups forming anions include, for example, acidicgroups or salts of acidic groups. The organic groups, therefore, includegroups derived from organic acids. Preferably, when it contains anionizable group forming an anion, such an organic group has a) anaromatic group and b) at least one acidic group having a pKa of lessthan 11, or at least one salt of an acidic group having a pKa of lessthan 11, or a mixture of at least one acidic group having a pKa of lessthan 11 and at least one salt of an acidic group having a pKa of lessthan 11. The pKa of the acidic group refers to the pKa of the organicgroup as a whole, not just the acidic substituent. More preferably, thepKa is less than 10 and most preferably less than 9. Preferably, thearomatic group of the organic group is directly attached to the carbonblack. The aromatic group may be further substituted or unsubstituted,for example, with alkyl groups. More preferably, the organic group is aphenyl or a naphthyl group and the acidic group is a sulfonic acidgroup, a sulfinic acid group, a phosphonic acid group, or a carboxylicacid group. Examples of these acidic groups and their salts arediscussed above. Most preferably, the organic group is a substituted orunsubstituted sulfophenyl group or a salt thereof; a substituted orunsubstituted (polysulfo)phenyl group or a salt thereof; a substitutedor unsubstituted sulfonaphthyl group or a salt thereof; or a substitutedor unsubstituted (polysulfo)naphthyl group or a salt thereof. Apreferred substituted sulfophenyl group is hydroxysulfophenyl group or asalt thereof.

Specific organic groups having an ionizable functional group forming ananion (and their corresponding primary amines) are p-sulfophenyl(p-sulfanilic acid), 4-hydroxy-3-sulfophenyl(2-hydroxy-5-amino-benzenesulfonic acid), and 2-sulfoethyl(2-aminoethanesulfonic acid). Other organic groups having ionizablefunctional groups forming anions can also be used.

Amines represent examples of ionizable functional groups that formcationic groups. For example, amines may be protonated to form ammoniumgroups in acidic media. Preferably, an organic group having an aminesubstituent has a pKb of less than 5. Quaternary ammonium groups (--NR₃⁺) and quaternary phosphonium groups (--PR₃ ⁺) also represent examplesof cationic groups. Preferably, the organic group contains an aromaticgroup such as a phenyl or a naphthyl group and a quaternary ammonium ora quaternary phosphonium group. The aromatic group is preferablydirectly attached to the carbon black. Quaternized cyclic amines, andeven quaternized aromatic amines, can also be used as the organic group.Thus, N-substituted pyridinium compounds, such as N-methyl-pyridyl, canbe used in this regard. Examples of organic groups include, but are notlimited to, (C₅ H₄ N)C₂ H₅ ⁺, C₆ H₄ (NC₅ H₅)⁺, C₆ H₄ COCH₂ N(CH₃)₃ ⁺, C₆H₄ COCH₂ (NC₅ H₅)⁺, (C₅ H₄ N)CH₃ ⁺, and C₆ H₄ CH₂ N(CH₃)₃ ⁺.

An advantage of the carbon black products having an attached organicgroup substituted with an ionic or an ionizable group is that the carbonblack product may have increased water dispersibility relative to thecorresponding untreated carbon black. Water dispersibility of a carbonblack product increases with the number of organic groups attached tothe carbon black having an ionizable group or the number of ionizablegroups attached to a given organic group. Thus, increasing the number ofionizable groups associated with the carbon black product shouldincrease its water dispersibility and permits control of the waterdispersibility to a desired level. It can be noted that the waterdispersibility of a carbon black product containing an amine as theorganic group attached to the carbon black may be increased byacidifying the aqueous medium.

Because the water dispersibility of the carbon black products depends tosome extent on charge stabilization, it is preferable that the ionicstrength of the aqueous medium be less than 0.1 molar. More preferably,the ionic strength is less than 0.01 molar.

When such a water dispersible carbon black product is prepared, it ispreferred that the ionic or ionizable groups be ionized in the reactionmedium. The resulting product solution or slurry may be used as is ordiluted prior to use. Alternatively, the carbon black product may bedried by techniques used for conventional carbon blacks. Thesetechniques include, but are not limited to, drying in ovens and rotarykilns. Overdrying, however, may cause a loss in the degree of waterdispersibility.

In addition to their water dispersibility, carbon black products havingan organic group substituted with an ionic or an ionizable group mayalso be dispersible in polar organic solvents such as dimethylsulfoxide(DMSO), and formamide. In alcohols such as methanol or ethanol, use ofcomplexing agents such as crown ethers increases the dispersibility ofcarbon black products having an organic group containing a metal salt ofan acidic group.

Aromatic sulfides encompass another group of preferred organic groups.Carbon black products having aromatic sulfide groups are particularlyuseful in rubber compositions. These aromatic sulfides can berepresented by the formulas Ar(CH₂)_(q) S_(k) (CH₂)_(r) Ar' orA--(CH₂)_(q) S_(K) (CH₂)_(r) Ar" wherein Ar and Ar' are independentlysubstituted or unsubstituted arylene or heteroarylene groups, Ar" is anaryl or heteroaryl group, k is 1 to 8 and q and r are 0-4. Substitutedaryl groups would include substituted alkylaryl groups. Preferredarylene groups include phenylene groups, particularly p-phenylenegroups, or benzothiazolylene groups. Preferred aryl groups includephenyl, naphthyl and benzothiazolyl. The number of sulfurs present,defined by k preferably ranges from 2 to 4. Preferred carbon blackproducts are those having an attached aromatic sulfide organic group ofthe formula --(C₆ H₄)--S_(k) --(C₆ H₄)--, where k is an integer from 1to 8, and more preferably where k ranges from 2 to 4. Particularlypreferred aromatic sulfide groups are bis-para-(C₆ H₄)--S₂ --(C₆ H₄)--and para-(C₆ H₄)--S₂ --(C₆ H₅). The diazonium salts of these aromaticsulfide groups may be conveniently prepared from their correspondingprimary amines, H₂ N--Ar--S_(k) --Ar'--NH₂ or H₂ N--Ar--S_(k) --Ar".Preferred groups include dithiodi-4,1-phenylene,tetrathiodi-4,1-phenylene, phenyldithiophenylene,dithiodi-4,1-(3-chlorophenylene), -(4-C₆ H₄)--S--S-(2-C₇ H₄ NS), -(4-C₆H₄)--S--S-(4-C₆ H₄)--OH, -6-(2-C₇ H₃ NS)--SH, -(4-C₆ H₄)--CH₂ CH₂--S--S--CH₂ CH₂ -(4-C₆ H₄)--, -(4-C₆ H₄)--CH₂ CH₂ --S--S--S--CH₂ CH₂-(4-C₆ H₄)--, -(2-C₆ H₄)--S--S-(2-C₆ H₄)--, -(3-C₆ H₄)--S--S-(3-C₆H₄)--, -6-(C₆ H₃ N₂ S), -6-(2-C₇ H₃ NS)--S--NRR' where RR' is --CH₂ CH₂OCH₂ CH₂ --, -(4-C₆ H₄)--S--S--S--S-(4-C₆ H₄)--, -(4-C₆ H₄)--CH═CH₂,-(4-C₆ H₄)--S--SO₃ H, -(4-C₆ H₄)--SO₂ NH-(4-C₆ H₄)--S--S-(4-C₆H₄)--NHSO₂ -(4-C₆ H₄)--, 6-(2-C₇ H₃ NS)--S--S-2-(6-C₇ H₃ NS)--, -(4-C₆H₄)--S--CH₂ -(4-C₆ H₄)--, -(4-C₆ H₄)--SO₂ --S-(4-C₆ H₄)--, -(4-C₆H₄)--CH₂ --S--CH₂ -(4-C₆ H₄)--, -(3-C₆ H₄)--CH₂ --S--CH₂ -(3-C₆ H₄)--,-(4-C₆ H₄)--CH₂ --S--S--CH₂ -(4-C₆ H₄)--, -(3-C₆ H₄)--CH₂ --S--S--CH₂-(3-C₆ H₄)--, -(4-C₆ H₄)--S--NRR' where RR' is --CH₂ CH₂ OCH₂ CH₂ --,-(4-C₆ H₄)--SO₂ NH--CH₂ CH₂ --S--S--CH₂ CH₂ --NHSO₂ -(4-C₆ H₄)--, -(4-C₆H₄)-2-(1,3-dithianyl;), and -(4-C₆ H₄)--S-(1,4-piperizinediyl)-S-(4-C₆H₄)-.

Another preferred set of organic groups which may be attached to thecarbon black are organic groups having an aminophenyl, such as (C₆H₄)--NH₂, (C₆ H₄)--CH₂ --(C₆ H₄)--NH₂, (C₆ H₄)--SO₂ --(C₆ H₄)--NH₂.Preferred organic groups also include aromatic sulfides, represented bythe formulas Ar--S_(n) --Ar' or Ar--S_(n) --Ar", wherein Ar and Ar' areindependently arylene groups, Ar" is an aryl and n is 1 to 8. Methodsfor attaching such organic groups to carbon black are discussed in U.S.patent applications Ser. Nos. 08/356,660, 08/572,525, and 08/356,459,the disclosures of which are fully incorporated by reference herein.

Furthermore, it is within the bounds of this application to also use amixture of silica and metal-treated carbon black. Also, any combinationof additional components with the metal-treated carbon black may be usedsuch as one or more of the following:

a) metal-treated carbon black with an attached organic group, optionallytreated with silane coupling agents;

b) silica;

c) modified silica, for example, having an attached organic group;and/or

d) other inorganic fillers and their chemically modified derivatives;

e) carbon black; and/or

f) modified carbon black having an attached organic group;

g) silicon-treated carbon black, optionally having attached organicgroups. Examples of silica include, but are not limited to, silica,precipitated silica, amorphous silica, vitreous silica, fumed silica,fused silica, silicates (e.g., alumina silicates) and other Sicontaining fillers such as clay, talc, wollastonite, etc. Silicas arecommercially available from such sources as Cabot Corporation under theCab-O-Sil® tradename; PPG Industries under the Hi-Sil and Ceptanetradenames; Rhone-Poulenc under the Zeosil tradename; and Degussa AGunder the Ultrasil and Coupsil tradenames.

The elastomeric compounds of the present invention may be prepared fromthe treated carbon blacks by compounding with any elastomer includingthose useful for compounding a carbon black.

Any suitable elastomer may be compounded with the metal-treated carbonblacks to provide the elastomeric compounds of the present invention.Such elastomers include, but are not limited to, rubbers, homo- orco-polymers of 1,3-butadiene, styrene, isoprene, isobutylene,2,3-dimethyl-1,3-butadiene, acrylonitrile, ethylene, and propylenePreferably, the elastomer has a glass transition temperature (Tg) asmeasured by differential scanning colorimetry (DSC) ranging from about-120° C. to about 0° C. Examples include, but are not limited,styrene-butadiene rubber (SBR), natural rubber, polybutadiene,polyisoprene, and their oil-extended derivatives. Blends of any of theforegoing may also be used.

Among the rubbers suitable for use with the present invention arenatural rubber and its derivatives such as chlorinated rubber. Themetal-treated carbon black products of the invention may also be usedwith synthetic rubbers such as: copolymers of from about 10 to about 70percent by weight of styrene and from about 30 to about 90 percent byweight of butadiene such as copolymer of 19 parts styrene and 81 partsbutadiene, a copolymer of 30 parts styrene and 70 parts butadiene, acopolymer of 43 parts styrene and 57 parts butadiene and a copolymer of50 parts styrene and 50 parts butadiene; polymers and copolymers ofconjugated dienes such as polybutadiene, polyisoprene, polychloroprene,and the like, and copolymers of such conjugated dienes with an ethylenicgroup-containing monomer copolymerizable therewith such as styrene,methyl styrene, chlorostyrene, acrylonitrile, 2-vinyl-pyridine, 5-methyl2-vinylpyridine, 5-ethyl-2-vinylpyridine, 2-methyl-5-vinylpyridine,alkyl-substituted acrylates, vinyl ketone, methyl isopropenyl ketone,methyl vinyl either, alphamethylene carboxylic acids and the esters andamides thereof such as acrylic acid and dialkylacrylic acid amide; alsosuitable for use herein are copolymers of ethylene and other high alphaolefins such as propylene, butene-1 and pentene-1.

The rubber compositions of the present invention can therefore containan elastomer, curing agents, reinforcing filler, a coupling agent, and,optionally, various processing aids, oil extenders, and antidegradents.In addition to the examples mentioned above, the elastomer can be, butis not limited to, polymers (e.g., homopolymers, copolymers, andterpolymers) manufactured from 1,3 butadiene, styrene, isoprene,isobutylene, 2,3-dimethyl-1,3 butadiene, acrylonitrile, ethylene,propylene, and the like. It is preferred that these elastomers have aglass transition point (Tg), as measured by DSC, between -120° C. and 0°C. Examples of such elastomers include poly(butadiene),poly(styrene-co-butadiene), and poly(isoprene).

Elastomeric compositions also include vulcanized compositions (VR),thermoplastic vulcanizates (TPV), thermoplastic elastomers (TPE) andthermoplastic polyolefins (TPO). TPV, TPE, and TPO materials are furtherclassified by their ability to be extruded and molded several timeswithout loss of performance characteristics.

In making the elastomeric compositions, one or more curing agents suchas, for example, sulfur, sulfur donors, activators, accelerators,peroxides, and other systems used to effect vulcanization of theelastomer composition may be used.

Formulation of the metal-treated carbon blacks of the present inventionwith elastomers are contemplated to have advantages not realized whensuch elastomers are formulated with conventional carbon blacks.

The following examples illustrate the invention without limitation.

EXAMPLES Example 1

Aluminum-treated carbon blacks according to the present invention wereprepared using a pilot scale reactor generally as described above, andas depicted in FIG. 1 and having the dimensions set forth below: D₁ =4inches, D₂ =2 inches, D₃ =5 inches, L₁ =4 inches, L₂ =5 inches, L₃ =7inches, L₄ =1 foot and Q=4.5 feet. The reaction conditions set forth inTable 1 below, were employed.

These conditions result in the formation of a carbon black identified bythe ASTM designation N234. A commercially available example of N234 isVulcan® 7H from Cabot Corporation, Boston, Mass. These conditions werealtered by adding a volatilizable aluminum-containing compound into thereactor, to obtain an aluminum-treated carbon black. The flow rate ofthe volatilizable compound was adjusted to alter the weight percent ofaluminum in the treated carbon black. The weight percent of aluminum inthe treated carbon black was determined by the ashing test, conductedaccording to ASTM procedure D-1506.

One such new treated carbon black was made by introducing a solution of70% Aluminum III s-Butoxide and 30% s-Butanol into the hydrocarbonfeedstock. This compound was obtained from Gelest Inc., Tullytown, Pa.The resultant aluminum-treated carbon blacks are identified herein asAl-CB1, Al-CB2 and AlCB4. A different aluminum-treated carbon black(Al-CB3) was prepared by introducing the aluminum-containingvolatilizable compound, into the reactor at location L₄.

Since changes in reactor temperature are known to alter the surface areaof the carbon black, and reactor temperature is very sensitive to thetotal flow rate of the feedstock in the injection zone (zone 3 in FIG.1), the feedstock flow rate was adjusted downward to approximatelycompensate for the introduction of the volatilizable aluminum-containingcompound, such that a constant reactor temperature was maintained. Thisresults in an approximately constant external surface area (as measuredby t area) for the resultant carbon blacks. All other conditions weremaintained as necessary for manufacturing N234 carbon black. No suchadjustment is needed when making sample Al-CB3, where thealuminum-containing compound was introduced into L₄. A structure controladditive (potassium acetate solution) was injected into the feedstock tomaintain the specification structure of the N234 carbon black. The flowrate of this additive was maintained constant in making thealuminum-treated carbon blacks described throughout the followingexamples.

The external surface area (t-area) was measured following the samplepreparation and measurement procedure described in ASTM D3037--Method Afor Nitrogen surface area. For this measurement, the nitrogen adsorptionisotherm was extended up to 0.55 relative pressure. The relativepressure is the pressure (P) divided by the saturation pressure (P₀)(the pressure at which the nitrogen condenses). The adsorption layerthickness (t₁) was then calculated using the relation: ##EQU1##

The volume (V) of nitrogen adsorbed was then plotted against t₁. Astraight line was then fitted through the data points for t₁ valuesbetween 3.9 and 6.2 Angstroms. The t-area was then obtained from theslope of this line as follows:

    t-area, m.sup.2 /gm=15.47×slope

                  TABLE 1                                                         ______________________________________                                        Conditions    A1-CB1  A1-CB2    A1-CB3                                                                              A1-CB4                                  ______________________________________                                        Air Rate, kscfh                                                                             12.8    12.8      12.8  12.8                                      Gas Rate, kscfh 1.033 1.029 1.028 1.036                                       Feedstock rate, lbs/hr 128 147 164 142                                        A1 compound rate, lbs/hr 32 8 8 16                                          ______________________________________                                    

The resultant carbon blacks were analyzed for surface area and aluminumcontent. These values are set forth in Table 2 below:

                  TABLE 2                                                         ______________________________________                                                 t-area                                                                             DBP         CDBP    % A1                                        ______________________________________                                        N234       119    125.8       101   0.03                                        A1-CB1 116 136 104 2.9                                                        A1-CB2 128 123 98 0.9                                                         A1-CB3 122 121 100 0.8                                                        A1-CB4 115 116 95 2.3                                                       ______________________________________                                    

Example 2

Preparation of Elastomeric Compositions

The carbon blacks of the previous Examples were used to make elastomericcompounds. Elastomeric compositions incorporating the aluminum-treatedcarbon blacks discussed above, were prepared using the followingelastomers: solution SBR (Duradene 715 from Firestone Synthetic Rubber &Latex Co., Akron, Ohio, and NS 116 from Nippon Zeon Co., Japan), BR(polybutadiene, Taktene 1203 from Bayer Inc., Akron, Ohio). Theelastomeric compositions were prepared according to the followingformulation:

                  TABLE 3                                                         ______________________________________                                                        N234 A1-CB                                                    ______________________________________                                        Solution SBR      75     75                                                     BR 25 25                                                                    N234              75     --                                                   A1-CB             --     75                                                     Si 69 ® (phr) -- 4.5                                                    Sundex 8125 ® 25     25                                                     Zinc oxide 3.5 3.5                                                            Stearic acid 2 2                                                              Flexzone 7P ® 1.5 1.5                                                     Sunproof Imp. ® 1.5 1.5                                                   Durax ® 1.5 1.5                                                         Vanax DPG ®   --     1.0                                                  TMTD              0.4    0.4                                                    sulfur 1.4 1.4                                                              ______________________________________                                    

Si 69®-bis(3-triethoxysilylpropyl)tetrasulfide, a coupling agent fromDegussa AG, Germany. Sundex 8125-highly aromatic oil, from R. E.Carroll, Trenton, N.J. Flexzone 7P®, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylene diamine, is an anti-oxidant available fromUniroyal Chemical Co., Middlebury, Conn. Sunproof Imp®.--Sunproofimproved, a mixture of waxy materials, from Uniroyal Chemical Co.,Middlebury, Conn. Durax®, N-cyclohexane-2-benzothiazole sulphenamide, isan accelerator available from R.T. Vanderbilt Co., of Norwalk, Conn.,and Captax®, 2-mercaptobenzothiazole, is an accelerator available fromR.T. Vanderbilt Co., Norwalk, Conn. Vanax DPG®--Diphenyl guanidine, anaccelerator available from R.T. Vanderbilt Co., of Norwalk, Conn.TMTD-Tetramethyl thiuram disulfide, an accelerator available from R. E.Carroll, Trenton, N.J. Sulfur-crosslinking agent from R. E. Carroll,Trenton, N.J.

The compounds were prepared using either a two-stage or three stagemixing procedure. The internal mixer used for preparing the compoundswas a Plasti-Corder EPL-V (obtained from C. W. Brabender, SouthHackensack, N.J.) equipped with a camtype mixing head (capacity 600 ml).In the first stage, the mixer was set at 80° C., and the rotor speed wasset at 60 rpm. In the case of three stage mixing, after the mixer wasconditioned to 100° C. by heating the chamber with a dummy mixture, theelastomer was loaded and masticated for 1 minute. Carbon blackpre-blended with coupling agent (Si 69 if any) was then added. Aftermixing for an additional 2.5 minutes, or when the temperature reached toabout 160° C., the oil was added. The stage 1 masterbatch was thendumped from the mixer at seven minutes total. This was then passedthrough an open mill three times and stored at room temperature for twohours. In the second stage, the mixing chamber temperature was set to80° C. and the rotor speed was set at 60 rpm. After the mixer wasconditioned to 100° C. by heating the chamber with a dummy mixture, themasterbach from first stage was loaded and masticated for 1 minute, thenzinc oxide and stearic acid were added. Flexzone 7P and wax (SunproofImproved) were added one minute later. In the last stage, the mixingchamber temperature was set to 80° C. and the rotor speed was set to 35rpm. After the mixer was conditioned the masterbatch from stage two wasloaded and mixed for one minute. The curative package (including sulfurand accelerators) was then added. The material was dumped from the mixerat two minutes and passed through the open mill three times.

Batches of the compounds were prepared as described for the carbonblacks in the previous Example. The conventional carbon black N234 wasused as a control. After mixing, each of the elastomeric compositionswas cured at 145° C. to an optimum cure state according to measurementsmade with a Monsanto ODR Rheometer.

Example 3

Dynamic Hysteresis and Abrasion Resistance

The dynamic hysteresis and abrasion resistance rates were measured forthe elastomeric compositions produced according to Example 2 above.

Abrasion resistance was determined using an abrader, which is based on aLambourn-type machine as described in U.S. Pat. No. 4,995,197, herebyincorporated by reference. The tests were carried out at 14% slip. Thepercentage slip is determined based on the relative velocities of asample wheel and a grindstone wheel. The abrasion resistance index iscalculated from the mass loss of the elastomeric compound. Dynamicproperties were determined using a Rheometrics Dynamic Spectrometer II(RDS II, Rheometrics, Inc., New Jersey) with strain sweep. Themeasurements were made at 0 and 70° C. with strain sweeps over a rangeof double strain amplitude (DSA) from 0.2 to 120%. The maximum tan δvalues on the strain sweep curves were taken for comparing thehysteresis among elastomeric compounds.

                  TABLE 4                                                         ______________________________________                                                  tan δ                                                                            tan δ                                                                            Abrasion Index                                      @ 0° C. @ 70° C. @ 14%                                        ______________________________________                                        Duradene 715/BR                                                                 N234 0.451 0.225 100                                                          A1-CB1 0.369 0.139 85.0                                                       A1-CB2 0.407 0.184 93.2                                                       A1-CB3 0.399 0.173 99.3                                                       A1-CB4 0.393 0.160 88.4                                                       NS116/BR                                                                      N234 0.448 0.241 100                                                          A1-CB1 0.410 0.129 83.4                                                       A1-CB2 0.451 0.177 101.1                                                      A1-CB3 0.447 0.157 93.9                                                       A1-CB4 0.431 0.154 89.5                                                     ______________________________________                                    

As seen in Table 4 above and in FIG. 2, tan δ values at 70° C. werereduced by 18.2˜38.2% for Duradene 715/BR system, and 26.6˜46.5% forNS116/BR polymer systems, while tan δ values at 0° C. were reduced by11.0˜18.2% for Duradene 715/BR compounds and -0.7˜8.4% for NS116/BRcompounds. For abrasion resistance, compared with N234, the maximumreduction is found for aluminum-treated carbon black for AB-CB1 with avalues of 15% and 16.6% in Duradene 715/BR and NS116/BR systems,respectively. AB-CB2 and AB-CB3 show a comparable abrasion resistance tothe traditional carbon black.

All patents, patent applications, test methods, and publicationsmentioned herein are incorporated by reference.

Many variations of the present invention will suggest themselves tothose skilled in the art in light of the above detailed disclosure. Forexample, the compositions of the present invention may include otherreinforcing agents, other fillers, oil extenders, antidegradants, andthe like. All such modifications are within the full intended scope ofthe claims.

What is claimed is:
 1. An elastomeric compound comprising an elastomerand aggregate comprising a carbon phase and a metal-containing speciesphase.
 2. The elastomeric compound of claim 1, wherein saidmetal-containing species comprises a magnesium-containing species phase,a calcium-containing species phase, a titanium-containing species phase,a vanadium-containing species phase, a cobalt-containing species phase,a nickel-containing species phase, a zirconium-containing species phase,a tin-containing species phase, an antimony-containing species phase, achromium-containing species phase, a neodymium-containing species phase,a lead-containing species phase, a tellurium-containing species phase, abarium-containing species phase, a cesium-containing species phase, aniron-containing species phase, a molybdenum-containing species phase, ormixtures thereof.
 3. The elastomeric compound of claim 1, wherein saidmetal-containing species phase comprises an aluminum-containing speciesphase.
 4. The elastomeric compound of claim 1, wherein saidmetal-containing species phase comprises a zinc-containing speciesphase.
 5. The elastomeric compound of claim 1, further comprising acoupling agent.
 6. The elastomeric compound of claim 1, wherein saidmetal-containing species phase exists primarily at the surface of themetal-treated carbon black aggregate.
 7. The elastomeric compound ofclaim 1, wherein said metal-containing species phase is distributedthroughout the metal-treated carbon black aggregate.
 8. The elastomericcompound of claim 1, wherein said elastomer comprises solution SBR,natural rubber, functional solution SBR, emulsion SBR, polybutadiene,polyisoprene, or blends thereof.
 9. The elastomeric compound of claim 1,further comprising a filler.
 10. The elastomeric compound of claim 1,wherein said metal-containing species phase is oxidized.
 11. Theelastomeric compound of claim 1, further comprising carbon black,silica, carbon black having an organic group attached thereto,silicon-treated carbon black or combinations thereof.
 12. Theelastomeric compound of claim 1, wherein at least a portion of saidmetal-treated carbon black aggregate has an organic group attachedthereto, and optionally treated with a silane coupling agent.
 13. Theelastomeric compound of claim 1, further comprising a carbon blackhaving an organic group attached thereto.
 14. The elastomeric compoundof claim 1, further comprising carbon black.
 15. The elastomericcompound of claim 1, wherein a portion of said metal-treated carbonblack aggregate has an organic group attached thereto and saidelastomeric compound further comprises a carbon black having an organicgroup attached thereto, silica, carbon black, or mixtures thereof. 16.The elastomeric compound of claim 1 wherein said metal-treated carbonblack metal-containing species phase comprises from about 0.1% to about25% elemental metal, by weight of said aggregate.
 17. The elastomericcompound of claim 16, wherein said metal-treated carbon blackmetal-containing species comprises from about 0.5% to about 10%elemental metal, by weight of said aggregate.
 18. The elastomericcompound of claim 17, wherein said metal-treated carbon blackmetal-containing species phase comprises from about 2% to about 6%elemental metal, by weight of said aggregate.
 19. The elastomericcompound of claim 5, wherein said coupling agent comprises a silanecoupling agent, a zirconate coupling agent, a titanate coupling agent, anitro coupling agent or a mixture thereof.
 20. The elastomeric compoundof claim 5, wherein said coupling agent comprisesbis(3-triethoxysilylpropyl)tetrasulfane, 3-thiocyanatopropyl-triethoxysilane, γ-mercaptopropyl-trimethoxy silane, zirconiumdineoalkanolatodi(3-mercapto)propionato-O,N,N'-bis(2-methyl-2-nitropropyl)-1,6-diaminohexane or mixtures thereof.21. The elastomeric compound of claim 5, wherein said coupling agentcomprises from about 0.1 to about 15 parts per hundred of elastomer. 22.An elastomeric compound comprising an elastomer and a metal-treatedcarbon black aggregate comprising a carbon phase and metal-containingspecies phase, wherein said elastomer comprises ethylene propylene dienemonomer rubber, poly chloroprene, natural rubber, polyisoprene,hydrogenated nitrile butadiene rubber, nitrile butadiene rubber,chlororinated polyethylene, styrene butadiene rubber, butyl rubber,polyacrylic rubber, polyepichlorohydrin, ethylene vinyl acetate, orblends thereof.
 23. The elastomeric compound of claim 22, wherein saidmetal-treated carbon black aggregate comprises from about 10 to about300 parts per hundred parts of said elastomer.
 24. The elastomericcompound of claim 23, wherein said metal-treated carbon black aggregatecomprises from about 100 to about 200 parts per hundred parts of saidelastomer.
 25. The elastomeric compound of claim 24, wherein saidmetal-treated carbon black aggregate comprises from about 10 to about150 parts per hundred parts of said elastomer.
 26. The elastomericcompound of claim 25, wherein said metal-treated carbon black aggregatecomprises about 20 to about 80 parts per hundred parts of saidelastomer.
 27. An article of manufacture formed from the elastomericcompound of claim
 22. 28. The elastomeric compound of claim 5 whereinsaid coupling agent comprises from about 0.1 to about 6 parts perhundred of elastomer.
 29. The elastomeric compound of claim 1, whereinsaid elastomer comprises a homopolymer, a copolymer, or terpolymer. 30.The elastomeric composition of claim 1, wherein said elastomer has aglass transition point, as measured by DSC, of less than 20° C.
 31. Theelastomeric composition of claim 30, wherein said elastomer has a glasstransition point, as measured by DSC, of between -120° C. and 0° C. 32.The elastomeric compound of claim 1, wherein said metal-treated carbonblack aggregate further comprises a silicon-containing species phase.33. The elastomeric compound of claim 1, wherein said metal-treatedcarbon black aggregate comprises at least two different metal-containingspecies phases.
 34. The elastomeric compound of claim 1, wherein saidmetal-treated carbon black aggregate further comprises aboron-containing species phase.